Safety assessment of oral administration of ethanol extract of Justicia carnea leaf in healthy wistar rats: hematology, antioxidative and histology studies

Abstract

Abstract Background Consumption of medicinal plants has diverse therapeutic benefits and could also have toxic effect. Justicia carnea is a medicinal plant that is used conventionally as blood tonic from time immemorial in Nigeria. The aim of this study is to evaluate the safety of ethanol extract of J. carnea leaf assessing the hematology indices, organ antioxidant system and histology in healthy male wistar rats. Methods Powdered sample was extracted using absolute ethanol and concentrated to obtain a slurry paste of J. carnea ethanol extracts. Acute toxicity was determined in two phases using Lorke method. In subacute study, rats were randomized into six groups of five rats per group: Group 1 (control) received distilled water, group 2, 3, 4, 5, 6 received 50, 100, 500, 800 and 1200 mg/kg body weight of J. carnea ethanol extract once daily using oral gavage. At the end of 14th day of administration, rats were allowed to fast overnight, sacrificed to collect samples for biochemical analysis and histopathological examination. Results The LD50 of extract was greater than 5000 mg/kg body weight. Higher doses (> 500 mg/kg) of extract significantly (p < 0.05) increased RBC, hemoglobin and platelet compared to the control. Liver superoxide dismutase (SOD) activity was significantly (p < 0.05) increased at 1200 mg/kg while other tested doses caused no detrimental effect on glutathione, catalase, SOD and malondialdehyde level in liver and kidney. Histopathological examination of liver and kidney showed mild to severe pathological lesion in a dose dependent manner. Conclusions The results of this study suggests that ethanol extract of J. carnea leaf is relatively safe, could be beneficial in alleviating hematology related abnormalities without causing adverse effects on endogenous antioxidant system. However, caution should be taken as higher dose at 1200 mg/kg could cause noticeable tissue injury.